Generally, a heat exchanger includes a tube in which a refrigerant flows and a heat exchanges with outside air, a heat exchanger fin in contact with the tube to widen a heat dissipation area, and a header in which both ends of the tube are communicated, and an evaporator or a condenser. The heat exchanger may constitute a refrigeration cycle together with a compressor for compressing the refrigerant and an expansion valve for expanding the refrigerant.
The refrigerant flows through the header and then through the header to the heat exchanger. The refrigerant may be heat-exchanged with the outside air while flowing inside the tube. At this time, as the refrigerant flows inside the tube, the amount of heat exchange increases as the refrigerant contacts with a large amount of outside air, thereby increasing the efficiency of the heat exchanger.